Gaerek is quite right about the laws in Nevada regarding concealed carry permit holders. I can't carry in a government building or a school, but private businesses can only ask me to leave. Their notices do not otherwise have force of law. But they do have force of moral authority. As much as I don't like Harrah's policy or attitudes towards those who carry a firearm for self-defense, I'm not going to just ignore their stated rules.
Nor will I miss the opportunity to tell them this, clearly and unmistakeably, so they know that those rules are costing them a customer.